Case Study: Grinder Saves The Day At Shickshinny Sewage Treatment Plant

The Borough of Shickshinny Sewer Plant faced a major operational problem. The plant, which has been in operation since 1979, services mostly residential areas, parts of two boroughs and a neighboring prison. It uses an activated sludge, secondary treatment process to process 500 MGD.

Even though Shickshinny's plant had a grinder located in front of the pumps, their pumps were still jamming frequently. The great deal of time and effort being expended to regularly maintain the pumps was becoming an unacceptable burden. The plant also had a comminutor. According to the plant supervisor, "it was an old type comminutor and wasn't very effective. It just didn't do the job". In spite of all this equipment it was still necessary to regularly rake solids from a manual bar screen. That's when the plant personnel turned to their consulting engineer for advice.

The engineer focused his attention on the operation of the grinder. It turned out this unit just wasn't strong enough to effectively handle the load and prevent overtaxing of the pumps. A new grinder was decided upon. The new unit, a Taskmaster^®, was designed for heavier duty service than their previous grinder. The Taskmaster employs counter-rotating banks of intermeshing cutters to intensively reduce waste solids.

Just as the time came to start up the new unit, the situation at the plant became critical. Only 15 minutes before the planned startup, the second of two pumps began to threaten to shut down. Since one pump was already out of operation, another failure would have caused serious trouble and the plant personnel were feeling the pressure. That's when the service engineer from Franklin Miller Inc. arrived. He was informed that the successful operation of the new unit was critical.